Method, system and equipment for calculating contribution of tire component to return rigidity and storage medium

Abstract

The invention relates to the technical field of tire simulation design, in particular to a method, a system and equipment for calculating contribution of a tire part to return rigidity and a storage medium. The method is based on a tire finite element model, and comprises the following steps: firstly, establishing a tire-rim-road surface contact model under rated inflation pressure and load working conditions, and calculating to obtain the reference return rigidity of the whole tire; then target parts such as a tread, a belted layer and sidewall rubber are selected, the Young modulus of the target parts is reduced to 0.01%-5% of a design value, inflation, loading and lateral deviation simulation are repeated on the premise that the geometric structure and boundary conditions are kept unchanged, and the return rigidity after degradation is obtained. The return rigidity difference value before and after degradation is compared, the return rigidity contribution value and contribution rate of each component are calculated according to the occurrence frequency of the component in the tire structure, and therefore the overall return rigidity is finely decomposed to the component level. According to the method, quantitative stripping of the return rigidity contribution of the tire is achieved, the method has the advantages of being small in error, good in repeatability and high in applicability, and a reliable basis can be provided for tire operation stability performance optimization.

Description

Technical Field

[0001] This invention relates to the field of tire simulation design technology, and in particular to a method, system, device and storage medium for calculating the contribution of tire components to self-alignment stiffness. Background Technology

[0002] In the fields of tire design and vehicle handling development, self-centering stiffness is a crucial indicator for evaluating a tire's ability to recover straight-line driving after lateral slippage, directly impacting vehicle straight-line stability and steering feel. Traditional engineering practices have focused more on overall stiffness indicators such as radial stiffness and lateral stiffness, with research on self-centering torque and self-centering stiffness primarily concentrating on macroscopic modeling and estimation of the entire tire, rather than refining the contribution decomposition to individual structural components.

[0003] For example, Chinese patent CN111191397A discloses a method for rapid prediction of the static radial stiffness of radial tires. This method involves meshing the tire material distribution map, assigning material properties, and using a two-dimensional axisymmetric finite element model for inflation and sweeping to generate a three-dimensional model. A load is applied to a rigid road surface to obtain a finite number of load-displacement data points. Then, the radial stiffness curve of the tire is obtained through mathematical model fitting, achieving rapid prediction of overall stiffness based on a combination of finite element and mathematical model. While this method improves the efficiency of radial stiffness prediction, its research object is the overall static radial stiffness of the tire, without considering the return stiffness, and it does not quantify the contribution of specific components such as the tread, belt layer, and sidewall to a particular stiffness index.

[0004] For example, Chinese patent CN104517039A proposes a semi-empirical modeling method for the steady-state self-correcting torque characteristics of tire roll and yaw. This method obtains test data of self-correcting torque under different vertical loads, yaw angles, and roll angles using a tire mechanical property test bench. The total self-correcting torque is decomposed into a nonlinear superposition of yaw lateral force self-correcting torque, roll lateral force self-correcting torque, and roll longitudinal force self-correcting torque. Curve fitting is used to identify model parameters, thereby establishing a steady-state self-correcting torque model suitable for vehicle dynamics simulation. This scheme has high accuracy and good predictive ability in macroscopic modeling of self-correcting torque, but it is still based on test data and equivalent models of the entire tire and cannot isolate the contribution of self-correcting stiffness from individual structural components at the finite element level.

[0005] Furthermore, Chinese patent CN103886142A discloses a method for estimating tire self-aligning torque based on expansion state variables. This method establishes a dynamic model of the steering rack mechanism and constructs a third-order nonlinear expansion state observer. During vehicle operation, it uses signals such as the input torque of the steering system and rack displacement to estimate the tire self-aligning torque online. This method has the advantages of not relying on dedicated sensors and being able to estimate online, making it suitable for engineering control applications. However, it is essentially a "black box" estimation scheme based on vehicle and steering system signals. It can only obtain the overall tire self-aligning torque or self-aligning stiffness, and cannot distinguish the independent contributions of local structures such as the tread, belt layer, and sidewall to the self-aligning stiffness.

[0006] In summary, existing technologies achieve rapid prediction of overall tire stiffness (such as radial stiffness) through finite element simulation and mathematical model fitting, and model and estimate the overall tire self-aligning torque online through test bench modeling or state observers. However, these solutions all focus on the "whole tire":

[0007] 1) Either a comprehensive prediction is made for a specific stiffness index (such as radial stiffness), without considering the normalizing stiffness;

[0008] 2) Either semi-empirical modeling or online estimation is performed for the restoring torque under complex working conditions, but the contributions of different structural components are not decoupled at the finite element level.

[0009] For tire design engineers, there is an urgent need during the structural optimization phase for a method that can directly and quantitatively evaluate the contribution of individual components to the self-alignment stiffness under uniform operating conditions and boundary conditions. This would allow for targeted adjustments to parameters such as tread stiffness, belt layer angle and stiffness, and sidewall stiffness. However, existing patents do not present a technical solution that uses a low-modulus degradation of the Young's modulus of the target component material in a finite element model, treating it as a mechanically "ineffective component," and then compares the changes in self-alignment stiffness before and after degradation while keeping boundary conditions constant, thereby quantitatively calculating the contribution value and rate of each component's self-alignment stiffness. Therefore, how to achieve the separation and quantification of tire component-level self-alignment stiffness contribution within the finite element simulation framework remains a problem that urgently needs to be solved. Summary of the Invention

[0010] The technical objective of this invention is to provide a simulation method that can quantitatively calculate the contribution of each structural component of a tire to its self-aligning stiffness under uniform working conditions and boundary conditions. By reducing the Young's modulus of the target component to a preset low modulus in the finite element model, it degenerates into a mechanically "ineffective component," and the change in self-aligning stiffness before and after degradation is compared, thereby obtaining the self-aligning stiffness contribution value and contribution rate of each component. This solves the technical problem in the prior art that can only obtain the overall stiffness of the tire but cannot reliably isolate the self-aligning stiffness contribution of a single component, and provides an accurate analytical basis for tire structure optimization design.

[0011] To achieve the objectives of this invention, the following technical solution is adopted:

[0012] A method for calculating the contribution of a tire component to its self-alignment stiffness includes the following steps:

[0013] 1) Establish a finite element model of the tire and perform inflation and load analysis:

[0014] 1.1) Based on the tire material distribution map, the tire cross section is divided into two-dimensional axisymmetric meshes, and the material properties of each component under the design state are assigned, including Young's modulus and Poisson's ratio. A rigid rim model is established, and the contact pair and friction coefficient are defined between the tire and the rim.

[0015] 1.2) Apply the rated inflation pressure to the inner boundary layer of the tire and perform two-dimensional axisymmetric inflation analysis to obtain equilibrium deformation;

[0016] 1.3) Based on the inflation analysis results, the two-dimensional axisymmetric model is rotated around the tire rotation axis to obtain a three-dimensional tire model. A rigid road surface model is established at a preset gap from the lower surface of the tire. The contact pair and friction coefficient between the tire and the road surface are defined. The rim is fixed, the rated load is applied to the rigid road surface, and the tire load analysis is performed.

[0017] 2) Calculate the tire's self-aligning stiffness reference value under rated inflation pressure and rated load conditions:

[0018] 2.1) Accelerate the three-dimensional tire model to a stable rolling speed on a rigid road surface, apply relative deflection between the tire and the road surface at multiple preset sideslip angles, and obtain the restoring torque around the load axis at each sideslip angle.

[0019] 2.2) The tire's reference self-aligning stiffness CMα1 is calculated based on the linear range of the self-aligning torque-side slip angle curve;

[0020] 3) Perform low-modulus degradation on the target component while maintaining the same operating conditions:

[0021] 3.1) Select at least one target component to be evaluated from the tire, and replace the material properties of the target component with an equivalent low modulus material in the finite element model, such that the Young's modulus of the equivalent low modulus material is 0.01% to 5% of the original Young's modulus, and the Poisson's ratio is the same as that of the raw material.

[0022] 3.2) Keep the material properties, tire geometry, contact relationships, loads, inflation pressure, and rolling speed of all components except the target component unchanged;

[0023] 4) Repeat the normalization stiffness calculation after low modulus degradation:

[0024] Under the operating conditions maintained in step 3.2), repeat steps 1.2) to 1.3) and step 2) to obtain the tire return stiffness CMα2 after changing the Young's modulus of the target component;

[0025] 5) Calculate the contribution of tire components to self-centering stiffness by normalizing the frequency of component occurrence:

[0026] Let the number of times the target component appears in the tire structure be n. According to the formula...

[0027] ΔC=|C Mα1 -C Mα2 | / n,

[0028] Calculate the return stiffness contribution value ΔC of the target component; and according to the formula...

[0029] η=ΔC / C Mα1 ,

[0030] Calculate the return stiffness contribution rate η of the target component.

[0031] Preferably, in step 1.1), the coefficient of friction between the tire and the rim is in the range of 0.01 to 1.0, and more preferably 0.02 to 0.1; in step 1.3), the coefficient of friction between the tire and the rigid road surface is in the range of 0.1 to 1.0, and more preferably 0.3 to 0.7.

[0032] Preferably, in step 2.1):

[0033] The stable rolling speed is 30-120 km / h, preferably 60 km / h;

[0034] The preset side slip angle range is -10° to 10°, and preferably the alignment rigidity C is obtained by linear fitting within the linear segment of -1° to 1°. Mα1 Or C Mα2 .

[0035] Preferably, in step 3.1), the Young's modulus of the target component is gradually reduced from the design value. Step 4) is repeated at each Young's modulus level. When the rate of change of the aligning stiffness corresponding to two adjacent Young's modulus settings is less than a preset threshold, the current Young's modulus is determined as the critical degradation modulus of the target component, and the aligning stiffness corresponding to this critical degradation modulus is used as C. Mα2 .

[0036] Preferably, the target component in step 3.1) is selected from at least one of the following: tread rubber, belt layer or crown layer, sidewall rubber, carcass ply, and bead component.

[0037] Preferably, in step 1.1), the rubber component adopts a hyperelastic constitutive model, preferably the Neo-Hookean model or the Mooney-Rivlin model, and the constitutive parameters are obtained by fitting based on actual material test data; the reinforcing layer component adopts a linear elastic anisotropic or orthotropic material model, thereby improving the accuracy of the normalization stiffness calculation.

[0038] Furthermore, the present invention also provides a calculation system for calculating the contribution of tire components to self-centering stiffness. The system includes a processor and a memory, wherein the memory stores a computer program executable on the processor, and the processor, when executing the computer program, is configured to implement the following functional modules:

[0039] The modeling module is used to generate a two-dimensional axisymmetric finite element model of the tire based on the tire material distribution map, assign material properties to each component under the design state, establish a rigid rim model, and set the contact pair and friction coefficient between the tire and the rim.

[0040] The inflation analysis module is used to apply a rated inflation pressure to the inner boundary layer of the tire and perform inflation analysis on the two-dimensional axisymmetric model to obtain equilibrium deformation.

[0041] The load analysis module is used to generate a three-dimensional tire model based on the inflation analysis results, establish a rigid road surface model located at the gap on the lower surface of the tire, set the contact pair and friction coefficient between the tire and the road surface, fix the rim, apply a rated load to the rigid road surface and perform tire load analysis.

[0042] The self-alignment stiffness calculation module is used to control the three-dimensional tire model to accelerate to a stable rolling speed on a rigid road surface under rated inflation pressure and rated load conditions. It applies relative deflection at multiple preset sideslip angles and extracts the self-alignment torque around the load axis. The self-alignment stiffness of the tire is calculated based on the linear interval of the self-alignment torque-slip angle curve.

[0043] The modulus degradation module is used to select a target component in the tire according to user input or preset rules, and replace the material properties of the target component in the finite element model with an equivalent low modulus material, so that the Young's modulus of the equivalent low modulus material is 0.01% to 5% of the original Young's modulus, and the Poisson's ratio is the same as that of the raw material, while keeping the material properties of other components, tire geometry, contact relationship and working parameters unchanged.

[0044] The repeat calculation module is used to repeat the inflation analysis, load analysis and return stiffness calculation after the modulus degradation module completes the degradation of the target component, so as to obtain the return stiffness of the degraded tire.

[0045] The contribution calculation module is used to calculate the normalizing stiffness C before degradation. Mα1 and the degraded restoring stiffness CMα2 And the number of times the target component appears in the tire structure, n, calculate the return stiffness contribution value ΔC=|C Mα1 -C Mα2 | / n and contribution rate η=ΔC / C Mα1 And output or store the corresponding contribution results.

[0046] Preferably, the modulus degradation module is further configured to: progressively reduce the Young's modulus of the target component according to a preset proportional sequence, and drive the repetitive calculation module to perform a normalization stiffness calculation for each level of Young's modulus; when the normalization stiffness change rate corresponding to two adjacent Young's moduli is less than a preset threshold, the current Young's modulus is determined to be the critical degradation modulus, and the normalization stiffness corresponding to the critical degradation modulus is taken as C. Mα2 Submit to the contribution calculation module;

[0047] And / or, the self-alignment stiffness calculation module is also configured to: based on the principle of motion relativity, release the tire's degree of freedom around the rotation axis in the simulation, and simulate the lateral slip condition by driving the road surface to move in the forward and lateral directions, thereby achieving rapid calculation and batch evaluation of self-alignment stiffness without changing the simplification of tire model constraints.

[0048] Furthermore, the present invention also provides an electronic device for calculating the contribution of a tire component to torsional stiffness, including a processor and a memory, wherein the memory stores a computer program that can run on the processor, and the processor executes the steps of the method when executing the computer program.

[0049] Furthermore, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, performs the steps of the method described thereon.

[0050] This invention achieves a quantifiable decomposition of the overall tire self-alignment stiffness contribution to the component level by introducing an analysis strategy of "low modulus degradation, completely unchanged operating conditions, and normalization based on the number of occurrences of components" within the finite element simulation framework. On the one hand, without changing the tire geometry, load, inflation pressure, and friction boundary conditions, by reducing the Young's modulus of the target component to 0.01% to 5% of the design value, it is equivalent to a mechanically "ineffective component." This allows for the stable isolation of the component's independent contribution to self-alignment stiffness, keeping the calculation error within ±2%, and significantly improving the accuracy and reproducibility of component contribution assessment. On the other hand, by defining ΔC and contribution rate η, and introducing normalization processing based on the number of occurrences n, it is possible not only to compare the influence weights of different components such as tread, belt layer, and sidewall on self-alignment stiffness under the same evaluation system, but also to sensitively capture the increase or decrease effects of local structural or material adjustments on self-alignment stiffness. This significantly shortens the trial-and-error cycle of tire structure optimization, reduces physical testing costs, and provides an efficient, refined, and visualized analysis tool for the coordinated optimization of tire formulation and structure with a handling and stability orientation. Attached Figure Description

[0051] Figure 1 This is a material distribution diagram for a 215 / 50R15 tire.

[0052] Figure 2 For 215 / 50R15 tire cross-section grid and material components;

[0053] Figure 3 The deformation results of a 215 / 50R15 tire after inflation;

[0054] Figure 4 The result of three-dimensional circumferential mesh generation for a 215 / 50R15 tire;

[0055] Figure 5 The curve showing the return torque and slip angle of a 215 / 50R15 tire;

[0056] Figure 6 This defines the tire coordinate system and boundary conditions. Detailed Implementation

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. A method for calculating the contribution of a tire component to envelope stiffness is described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0058] I. Overall Approach and System Environment

[0059] The method of this invention relies on a finite element simulation platform to calculate the component-level contribution of tire self-alignment stiffness. By performing low-modulus degradation on the Young's modulus of the target component's material under the same geometric model and boundary conditions, the component is equivalent to a mechanically "ineffective component," and the change in self-alignment stiffness before and after degradation is compared, thereby quantitatively obtaining the self-alignment stiffness contribution value and contribution rate of the component.

[0060] In a preferred embodiment, the simulation environment can be a combination of self-developed tire finite element pre- and post-processing software and a general finite element solver. For example, it can use pre-processing techniques similar to those described in "Method for Rapid Generation of Tire Two-Dimensional Geometric Model Mesh" (publication number CN116451479A) and "Automatic Identification Method for Tire Pre-processing Components" (publication number CN117171882A) to achieve automatic identification and mesh generation of tire geometry and component division. The solver can be an explicit or implicit finite element solver that supports nonlinear contact and large deformation analysis.

[0061] II. Example 1: Establishment of a Tire Finite Element Model (corresponding to...) Figure 1 , Figure 2 , Figure 6 )

[0062] 1. Tire geometry model and component identification

[0063] Reference Figure 1 This embodiment uses a 215 / 50R15 passenger car tire as an example. The tire section consists of the following main components:

[0064] Tread components: including tread compound and any base compound that may be present;

[0065] Belt layer / crown layer component: composed of multiple layers of steel belt curtains or fiber curtains;

[0066] Tire body components: tire carcass ply and its rubber overlay;

[0067] Sidewall rubber components: located on the outside of the tire carcass, used to provide lateral flexibility and protection;

[0068] Tire bead components: including bead wire, bead wrapping fabric, bead core adhesive, etc.

[0069] In practical implementation, tire material distribution diagrams can be imported from tire design drawings (CAD cross-sectional views), and pre-processing programs can be used to automatically identify the boundaries of each component and mark them as different geometric regions, such as... Figure 1 As shown.

[0070] 2. Two-dimensional axisymmetric mesh generation

[0071] like Figure 2 As shown, a two-dimensional axisymmetric mesh is generated for the material distribution map. The implementation steps are as follows:

[0072] 1) Establish a two-dimensional axisymmetric geometric model in the r–z plane with the tire's axis of symmetry as the axis of rotation;

[0073] 2) Divide the tread, sidewall, carcass, bead and other areas into units of appropriate size. The rubber parts are preferably made of four-node axisymmetric units, and the reinforcement layer can be made of embedded units or shell-solid coupled units.

[0074] 3) The mesh size selection takes into account both calculation accuracy and efficiency, and the mesh size in the tread and belt layer areas is appropriately fined to more accurately capture the stress and deformation near the contact surface;

[0075] 4) The tire carcass ply can be modeled using a “shell element + equivalent thickness” approach, or solid elements can be used and the direction of the cord can be achieved through material anisotropy.

[0076] 3. Material Model and Parameter Assignment

[0077] In this embodiment, the rubber component adopts a hyperelastic material model, preferably the Neo-Hookean model; the reinforcing layer adopts a linear elastic anisotropic material model. The stress-strain relationship of the rubber material can be expressed as:

[0078] ;

[0079] in:

[0080] Let be the strain energy function;

[0081] These are material constants, obtained through fitting experiments such as uniaxial tensile and planar tensile tests;

[0082] It is the first invariant.

[0083] The reinforcing layer material adopts an equivalent Young's modulus Compared to Poisson The description emphasizes the application of greater stiffness in the material direction and relatively less stiffness in the vertical direction to reflect the cord constraint characteristics.

[0084] 4. Contact Relationship and Friction Coefficient Settings

[0085] See Figure 6 In a two-dimensional model, a contact pair between the tire and the rigid rim is established: the rim is modeled as a rigid body or a high-rigidity solid; the inner surface of the tire and the outer surface of the rim are defined as surface-to-surface contact; the coefficient of friction is preferably set to 0.03, and the method of this invention is applicable to cases with a coefficient of friction in the range of 0.01 to 1.0. During the inflation stage, road contact is not introduced; only the tire-rim contact is defined.

[0086] III. Example 2: Inflation Analysis (corresponding to) Figure 3 )

[0087] 1. Inflation mode settings

[0088] Within the axisymmetric finite element model, the inner element surface closest to the tire cavity surface is selected as the "internal boundary layer," and the cavity pressure is applied to this region. Taking this embodiment as an example: the rated inflation pressure is set to 250 kPa; the pressure is applied statically, in 3 to 5 sub-steps to improve convergence stability.

[0089] 2. Solution process and results

[0090] An implicit statics solver is used for nonlinear analysis, considering large geometric deformation and contact nonlinearity. Once the residual unbalanced force is below a preset convergence threshold, the equilibrium deformation state of the tire under rated air pressure is obtained.

[0091] Figure 3 The deformation results after inflation are shown, including:

[0092] Sidewall bulge;

[0093] Changes in tread width;

[0094] Stress distribution cloud diagrams for each component.

[0095] This state is used for subsequent 3D model generation and load analysis, and is one of the initial working conditions for the return-to-normal rigidity calculation in the method of this invention.

[0096] IV. Example 3: Three-dimensional tire model and load analysis (corresponding) Figure 3 , Figure 4 , Figure 6 )

[0097] 1. 3D model generation

[0098] After completing the axisymmetric inflation analysis, the two-dimensional model is rotated 360° around the tire's rotation axis (z-axis) to generate the following result: Figure 4 The three-dimensional tire model shown can be implemented in the following two ways:

[0099] 1) Circumferential uniform grid: Divide the two-dimensional grid into several blocks along the circumference (e.g., 72 blocks, each at 5°), which is suitable for cases where the pattern is simplified or ignored;

[0100] 2) Circumferentially Non-uniform Mesh: When circumferential non-uniformity needs to be considered (e.g., differences in stiffness between patterned blocks), a refined or locally densified mesh can be added to the patterned area to form a mesh like... Figure 4 The non-uniform block division shown on the right.

[0101] The method of this invention is applicable to both circumferentially uniform and non-uniform meshes, as long as the geometry and mesh topology remain consistent before and after degradation.

[0102] 2. Road surface model and contact definition

[0103] Reference Figure 6 Create a rigid, flat surface under the tires:

[0104] The initial position of the road surface is approximately 1 mm away from the lowest point of the tire tread;

[0105] The road surface is modeled as a rigid flat plate, with its plane normal opposite to the radial direction of the tire.

[0106] In the 3D model, the contact pairs between the outer surface of the tire and the rigid road surface are defined in a face-to-face contact manner.

[0107] The coefficient of friction is preferably set to 0.5, and the applicable range is 0.1 to 1.0.

[0108] 3. Load application and boundary conditions

[0109] During the load analysis phase:

[0110] 1) The translational degree of freedom of the fixed rim rigid body allows it to rotate freely around the tire's axis of rotation, simulating rolling conditions;

[0111] 2) Apply an equivalent vertical load to a rigid road surface. For example, in this embodiment, the rated load is 4802 N;

[0112] 3) It can simultaneously apply forward direction constraints and driving force to the tires or road surface, causing the tires to roll on the road surface at a predetermined speed.

[0113] The solver calculates the contact patch and internal stress state of the tire under the combined conditions of rated inflation pressure and rated load. This condition will be used in the next step for calculating the return stiffness.

[0114] V. Example 4: Calculation of return stiffness (corresponding to) Figure 5 )

[0115] 1. Stable rolling and sideslip angle setting

[0116] In this embodiment, the principle of relativity of motion is used to simplify the modeling:

[0117] 1) Fix the tire coordinate system and make the tire rotate around the rotation axis at an equivalent angular velocity to simulate the vehicle's forward speed of 60km / h;

[0118] 2) Relative motion is achieved by moving a rigid road surface, that is, the road surface moves in the forward direction at a linear velocity that matches the rotation of the tire, thus forming an equivalent rolling condition.

[0119] 3) After achieving stable rolling, apply a sideslip angle between the tire and the road surface. This can be achieved by rotating the longitudinal axis of the tire or rotating the direction of road movement.

[0120] In a specific example, the sideslip angle ranges from -10° to 10°, with a step size of 1°. For each sideslip angle condition, the corresponding restoring torque is calculated under stable rolling conditions. .

[0121] 2. Extraction of the restoring torque

[0122] The restoring torque is defined as the torque about a load axis perpendicular to the road surface. In finite element analysis, it can be obtained as follows:

[0123] 1) Integrate the contact forces of each element on the contact surface and calculate the torque about the tire center;

[0124] 2) Take its component about the load axis as the restoring torque. .

[0125] Get a set Data, i.e. Figure 5 The curve shown is a return torque versus sideslip angle curve.

[0126] 3. Calculation of return stiffness

[0127] Within the small sideslip angle range, the self-aligning torque is approximately linearly related to the sideslip angle. In this embodiment, the range of -1° to 1° is selected for linear fitting. Self-aligning rigidity Defined as:

[0128] ;

[0129] in:

[0130] Indicates tire self-alignment stiffness (unit: Nm / °);

[0131] This represents the difference in the restoring torque between the endpoints of the linear interval;

[0132] This represents the corresponding difference in sideslip angle.

[0133] Under the baseline operating condition of this embodiment (i.e., all components are at their design modulus), by Figure 5 available:

[0134] ;

[0135] in:

[0136] Indicates the reference return stiffness;

[0137] 59.3 N·m and -74.6 N·m are respectively and The restoring torque at that time;

[0138] 2° is the difference between the two sides of the deflection angle.

[0139] VI. Example 5: Degradation and Repeatability Analysis of Young's Modulus of Target Component (Corresponding) Figures 2-5 )

[0140] 1. Selection of target components

[0141] The key step of this invention lies in performing low-modulus degradation on the target component. Taking a tread component as an example:

[0142] exist Figure 2 In the cross-sectional mesh shown, all elements of the tread region are identified by component attributes or geometric grouping;

[0143] The number of times the tread appears in the tire structure is: For symmetrical tread structures, typically For symmetrical sidewall rubber, then .

[0144] Of course, the target components are not limited to the tread; any one or more components such as the belt layer, sidewall rubber, and carcass ply can also be selected.

[0145] 2. Young's modulus degradation strategy

[0146] In the finite element model, the Young's modulus of the target component is changed from the design value. Gradually reduce to the preset low modulus ratio range (0.01% to 5%). For example:

[0147] Level 1 is set as ;

[0148] The second level is set as follows: ;

[0149] Level 3 is set as .

[0150] In each stage of degradation, the Poisson's ratio is kept consistent with that of the raw material to ensure that the volumetric compression characteristics do not change abruptly, only weakening its load-bearing stiffness, so that the component gradually approaches the state of "mechanical ineffectiveness".

[0151] 3. Constant operating conditions and repeated solutions

[0152] After degradation, repeat the following steps:

[0153] 1) Re-perform the inflation analysis using the degraded two-dimensional model, applying the same rated pressure of 250 kPa;

[0154] 2) Generate a three-dimensional tire model based on the new inflation balance state;

[0155] 3) Load analysis was performed under the same road surface model, the same friction coefficient, the same rated load of 4802N, and the same rolling speed of 60km / h;

[0156] 4) Extract the aligning torque under the same sideslip angle sequence (-10° to 10°, step size 1°) and plot the new aligning torque-sidelip angle curve;

[0157] 5) Calculate the post-degradation restoring stiffness within the same linear interval (-1° to 1°). .

[0158] Taking the case where the Young's modulus of the tread degrades to 1% of its design value as an example, this embodiment yields:

[0159] ;

[0160] in:

[0161] The return stiffness after the target component degrades;

[0162] 54.3 N·m and -75.9 N·m are the normalizing torques at the corresponding sideslip angles.

[0163] By comparing different degradation ratios When the Young's modulus is further reduced, the change in the aligning stiffness tends to saturate. That is, when the rate of change of the difference in aligning stiffness between two adjacent degradation levels is lower than a preset threshold (e.g., 1%), the current degradation ratio can be considered sufficient to regard the component as a "mechanically ineffective component". In this embodiment, 1% is selected as a suitable degradation ratio.

[0164] VII. Example 6: Calculation of the contribution value and contribution rate of the stiffening mechanism (corresponding to...) Figure 5 )

[0165] After obtaining the reference return stiffness and the return stiffness after the target component degrades Then, the return stiffness contribution value and contribution rate of the target component can be calculated.

[0166] 1. Calculation of contribution value

[0167] Define the number of times the target component appears in the tire structure as The contribution value of the target component to the return stiffness. for:

[0168] ;

[0169] in:

[0170] Contribution to the return stiffness of the target component (unit: N·m / °);

[0171] As a reference for calibrating rigidity;

[0172] The return stiffness after the target component degrades;

[0173] This represents the number of times the component appears.

[0174] If the tread only appears once Therefore:

[0175] ;

[0176] 2. Calculation of Contribution Rate

[0177] Define the contribution rate of the stiffness return. The proportion of the contribution value of the target component relative to the reference return stiffness:

[0178] ;

[0179] in:

[0180] Contribution rate to the return stiffness of the target component (dimensionless or expressed as a percentage).

[0181] Substitute specific data:

[0182] ;

[0183] That is, the contribution of the tread components to the overall self-aligning rigidity of the tire is about 3%.

[0184] pass Figure 5 The comparison of the two curves (before and after degradation) shows that the aligning stiffness decreases slightly after the Young's modulus of the tread decreases, and the slope of the linear region decreases by about 3%, which verifies the above quantitative calculation results.

[0185] VIII. Technical Effects and Application Expansion

[0186] 1. Component-level contribution visualization and sensitivity analysis

[0187] Using the above method, Young's modulus degradation analysis can be performed on multiple components such as the tread, belt layer, sidewall rubber, carcass ply, and bead, and their respective results can be obtained. and Then, these are summarized to form a "component contribution spectrum".

[0188] For example:

[0189] Tread: Contribution rate approximately 3%;

[0190] Belt layer: Contribution rate approximately 15%–20%;

[0191] Sidewall rubber: Contributes approximately 10%, etc.

[0192] In this way, design engineers can intuitively determine which type of component is most sensitive to return stiffness, and thus adjust the relevant structural and material parameters accordingly, without relying on a large number of physical prototypes and tests.

[0193] 2. Rapid evaluation for various specifications and operating conditions

[0194] The method of this invention does not depend on specific tire specifications or specific operating conditions. As long as a corresponding finite element model is established and the corresponding inflation pressure and load are set, similar analyses can be performed. For example:

[0195] For SUV, high-performance sedan or light truck tires, only the material distribution diagram and operating parameters need to be replaced.

[0196] For different inflation pressures and load scenarios, you only need to adjust the inflation pressure and load settings in the steps to obtain the return stiffness contribution under each working condition.

[0197] 3. Integration with handling simulation and subjective evaluation

[0198] Since self-centering stiffness is one of the core parameters of vehicle handling characteristics (such as self-centering feel and straight-line stability), the component-level self-centering stiffness contribution obtained in this invention can be further used as input to the higher-level vehicle dynamics model for:

[0199] Adjust the tire return stiffness parameter in a multibody dynamics model to evaluate the impact of structural changes on the vehicle's return feel.

[0200] Guided formulation improvements and structural adjustments to enhance handling stability while ensuring comfort and durability.

[0201] 4. Closed-loop calibration with test data

[0202] In practical engineering, the finite element calculation results of this invention can be compared with the self-aligning stiffness measured on a tire testing bench, through:

[0203] For rubber material model parameters (such as) Make minor adjustments;

[0204] Correct the equivalent modulus and angle of the reinforcing layer;

[0205] Achieving consistency calibration between simulation and experiment. The calibrated simulation model is then used for component-level contribution calculation in the method of this invention, which can further improve the reliability of the calculation results.

[0206] 5. Different Constitutive Model Selection

[0207] Other hyperelastic models such as Mooney-Rivlin and Ogden can be used for rubber materials. As long as the overall stiffness and the accuracy of the normalization stiffness prediction are guaranteed by fitting the parameters through experiments, the low modulus degradation and contribution calculation method of this invention is also applicable.

[0208] 6. Different degradation strategies

[0209] In addition to “gradually reducing Young’s modulus”, the Young’s modulus of the target component can also be set to a fixed percentage of the original value (such as 1%). If it is verified that the change in normalized stiffness has become stable, then multi-level degradation iterations can be eliminated to improve computational efficiency.

[0210] 7. Multi-component joint degradation

[0211] In some cases, multiple components can be degraded simultaneously to obtain a joint contribution value. Then, the contribution range of a single component or a group of components can be derived through combinatorial analysis. This approach is suitable for situations where the local structure is highly coupled and difficult to completely decouple.

[0212] 8. Different sideslip angle control schemes

[0213] In addition to achieving the sideslip angle by rotating the tire or moving the road surface, the sideslip effect can also be generated by applying an equivalent lateral velocity or lateral displacement boundary in the tire coordinate system. This invention does not limit the way the sideslip angle is achieved.

[0214] As can be seen from the above embodiments, this invention, within the framework of finite element simulation, achieves the technical path of "quantitatively separating the contribution of a target component to its self-aligning rigidity by reducing its low modulus degradation under completely unchanged operating conditions." This method can not only control the contribution error of each component within ±2%, but also provide refined and visualized design basis for tire structure optimization and handling performance improvement through contribution values ​​and contribution rates.

[0215] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for calculating the contribution of a tire component to its self-alignment stiffness, characterized by comprising the following steps: 1) Establish a finite element model of the tire and perform inflation and load analysis: 1.1) Based on the tire material distribution map, the tire cross section is divided into two-dimensional axisymmetric meshes, and the material properties of each component under the design state are assigned, including Young's modulus and Poisson's ratio. A rigid rim model is established, and the contact pair and friction coefficient are defined between the tire and the rim. 1.2) Apply the rated inflation pressure to the inner boundary layer of the tire and perform two-dimensional axisymmetric inflation analysis to obtain equilibrium deformation; 1.3) Based on the inflation analysis results, the two-dimensional axisymmetric model is rotated around the tire rotation axis to obtain a three-dimensional tire model. A rigid road surface model is established at a preset gap from the lower surface of the tire. The contact pair and friction coefficient between the tire and the road surface are defined. The rim is fixed, the rated load is applied to the rigid road surface, and the tire load analysis is performed. 2) Calculate the tire's self-aligning stiffness reference value under rated inflation pressure and rated load conditions: 2.1) Accelerate the three-dimensional tire model to a stable rolling speed on a rigid road surface, apply relative deflection between the tire and the road surface at multiple preset sideslip angles, and obtain the restoring torque around the load axis at each sideslip angle. 2.2) Based on the linear range of the self-aligning torque-slip angle curve, the tire's reference self-aligning stiffness C is calculated. Mα1 ; 3) Perform low-modulus degradation on the target component while maintaining the same operating conditions: 3.1) Select at least one target component to be evaluated from the tire, and replace the material properties of the target component with an equivalent low modulus material in the finite element model, such that the Young's modulus of the equivalent low modulus material is 0.01% to 5% of the original Young's modulus, and the Poisson's ratio is the same as that of the raw material. 3.2) Keep the material properties, tire geometry, contact relationships, loads, inflation pressure, and rolling speed of all components except the target component unchanged; 4) Repeat the normalization stiffness calculation after low modulus degradation: Under the operating conditions maintained in step 3.2), repeat steps 1.2) to 1.3) and step 2) to obtain the tire return stiffness C after changing the Young's modulus of the target component. Mα2 ; 5) Calculate the contribution of tire components to self-centering stiffness by normalizing the frequency of component occurrence: Let the number of times the target component appears in the tire structure be n. According to the formula... ΔC=|C Mα1 -C Mα2 | / n, Calculate the return stiffness contribution value ΔC of the target component; And according to the formula η=ΔC / C Mα1 , Calculate the return stiffness contribution rate η of the target component.

2. The method according to claim 1, characterized in that, In step 1.1), the coefficient of friction between the tire and the rim is in the range of 0.01 to 1.0, preferably 0.02 to 0.1; in step 1.3), the coefficient of friction between the tire and the rigid road surface is in the range of 0.1 to 1.0, preferably 0.3 to 0.

7.

3. The method according to claim 1, characterized in that, In step 2.1): The stable rolling speed is 30-120 km / h, preferably 60 km / h; The preset side slip angle range is -10° to 10°, and preferably the alignment rigidity C is obtained by linear fitting within the linear segment of -1° to 1°. Mα1 Or C Mα2 .

4. The method according to claim 1, characterized in that, In step 3.1), the Young's modulus of the target component is gradually reduced from the design value. Step 4) is repeated at each Young's modulus level. When the rate of change of the normalizing stiffness corresponding to two adjacent Young's modulus settings is less than a preset threshold, the current Young's modulus is determined as the critical degradation modulus of the target component, and the normalizing stiffness corresponding to this critical degradation modulus is used as C. Mα2 .

5. The method according to claim 1, characterized in that, The target component in step 3.1) is selected from at least one of the following: tread rubber, belt layer or crown layer, sidewall rubber, carcass ply, and bead component.

6. The method according to claim 1, characterized in that, In step 1.1), the rubber component adopts a hyperelastic constitutive model, preferably the Neo-Hookean model or the Mooney-Rivlin model, and the constitutive parameters are obtained by fitting based on actual material test data; the reinforcing layer component adopts a linear elastic anisotropic or orthotropic material model, thereby improving the accuracy of the normalization stiffness calculation.

7. A calculation system for calculating the contribution of tire components to self-alignment stiffness, characterized in that, The system includes a processor and a memory, the memory storing a computer program that can run on the processor, the processor being configured to implement the following functional modules when executing the computer program: The modeling module is used to generate a two-dimensional axisymmetric finite element model of the tire based on the tire material distribution map, assign material properties to each component under the design state, establish a rigid rim model, and set the contact pair and friction coefficient between the tire and the rim. The inflation analysis module is used to apply a rated inflation pressure to the inner boundary layer of the tire and perform inflation analysis on the two-dimensional axisymmetric model to obtain equilibrium deformation. The load analysis module is used to generate a three-dimensional tire model based on the inflation analysis results, establish a rigid road surface model located at the gap on the lower surface of the tire, set the contact pair and friction coefficient between the tire and the road surface, fix the rim, apply a rated load to the rigid road surface and perform tire load analysis. The self-alignment stiffness calculation module is used to control the three-dimensional tire model to accelerate to a stable rolling speed on a rigid road surface under rated inflation pressure and rated load conditions. It applies relative deflection at multiple preset sideslip angles and extracts the self-alignment torque around the load axis. The self-alignment stiffness of the tire is calculated based on the linear interval of the self-alignment torque-slip angle curve. The modulus degradation module is used to select a target component in the tire according to user input or preset rules, and replace the material properties of the target component in the finite element model with an equivalent low modulus material, so that the Young's modulus of the equivalent low modulus material is 0.01% to 5% of the original Young's modulus, and the Poisson's ratio is the same as that of the raw material, while keeping the material properties of other components, tire geometry, contact relationship and working parameters unchanged. The repeat calculation module is used to repeat the inflation analysis, load analysis and return stiffness calculation after the modulus degradation module completes the degradation of the target component, so as to obtain the return stiffness of the degraded tire. The contribution calculation module is used to calculate the normalizing stiffness C before degradation. Mα1 and the degraded restoring stiffness C Mα2 And the number of times the target component appears in the tire structure, n, calculate the return stiffness contribution value ΔC=|C Mα1 -C Mα2 | / n and contribution rate η=ΔC / C Mα1 And output or store the corresponding contribution results.

8. The system according to claim 8, characterized in that, The modulus degradation module is further configured to: progressively reduce the Young's modulus of the target component according to a preset proportional sequence, and drive the repetitive calculation module to perform a normalization stiffness calculation for each level of Young's modulus. When the normalization stiffness change rate corresponding to two adjacent Young's moduli is less than a preset threshold, the current Young's modulus is determined to be the critical degradation modulus, and the normalization stiffness corresponding to the critical degradation modulus is taken as C. Mα2 Submit to the contribution calculation module; And / or, the self-alignment stiffness calculation module is also configured to: based on the principle of motion relativity, release the tire's degree of freedom around the rotation axis in the simulation, and simulate the lateral slip condition by driving the road surface to move in the forward and lateral directions, thereby achieving rapid calculation and batch evaluation of self-alignment stiffness without changing the simplification of tire model constraints.

9. An electronic device for calculating the contribution of a tire component to torsional stiffness, characterized in that, The method includes a processor and a memory, wherein the memory stores a computer program that can run on the processor, and the processor, when executing the computer program, performs the steps of the method as described in any one of claims 1 to 6.

10. A computer-readable storage medium having a computer program stored thereon, the computer program, when executed by a processor, performing the steps of the method as described in any one of claims 1 to 6.

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